The Trouble With Background Noise

By

Ann Lukits

Dec. 3, 2012 10:20 p.m. ET

Everyday background noise, whether it is a neighbor's television or passing aircraft, can have a disruptive effect on people's cognitive learning and unconscious physiological processes, says a study in the International Journal of Hygiene and Environmental Health. The health hazards of loud noise are well studied, but low-intensity background noise has received less attention, researchers said.

The study tested the computer learning abilities of 59 Austrians in their mid-20s in a room with varying background noise. Each was required to study three computer texts for 15 minutes and then were tested on their knowledge.

ENLARGE

Everyday background noise, whether it is a neighbor's television or passing aircraft, can have a disruptive effect on people's cognitive learning and unconscious physiological processes, says a study in the International Journal of Hygiene and Environmental Health.
Matt Collins

One group of 20 was exposed to low-level noise of 36 decibels during the tests. (Normal conversation is 50 to 60 decibels.)

A second group of 20 was exposed to 45 decibels of garbled noise from a comedy CD played backward in an adjacent room.

A third group, with 19 subjects, was exposed to the simulated noise—about 46 decibels—of a distant aircraft approaching an airport at a rate of one per minute. Heart rate and galvanic skin responses, both autonomic indicators of stress, were measured throughout the learning period for the three tests.

Memory scores were higher in the control group than in both the aircraft- and neighborhood-noise groups. In one test, it was significantly higher than the three aircraft-noise tests. Skin conductance rates in the aircraft-noise group were significantly higher than in control subjects throughout most of the study, and higher than the neighborhood-noise group in the final five minutes of text learning.

Heart rates in the aircraft group also increased significantly in these last five minutes. Aircraft noise may place a higher demand on attention and sympathetic physiological responses such as heart rate and perspiration than other types of noise, researchers said.

Caveat: The aircraft noise had a broader spectrum compared with the other noise sources and may have been perceived as louder, triggering psychological effects, such as thoughts of an attack from above, researchers said. Some people are more sensitive to background noise than others, they said.

Medication errors: A study in the Journal of Pediatric Health Care found that 25% of parents were unable to correctly measure a dose of children's cough syrup, but the wording of the instructions had little effect on accuracy. Research has shown that dosing errors are common with liquid medications, often because of ambiguous instructions and the type of measuring device used.

The study involved 193 U.S. women in their late 20s. About a third were college educated and 80% had children. Health literacy, the capacity to understand medical-related information, was adequate in 99, marginal in 58 and inadequate in 36, tests showed.

The subjects received identical medication bottles with instructions to shake well before measuring 6 milliliters of the liquid. In 96 cases, the instructions were implicit, or indicated the medication should be given every 12 hours. For 97 subjects, the instructions explicitly stated the medication be given at 7 a.m. and 7 p.m. A 10-milliliter needleless syringe was used by 86% of subjects, a 5-milllimeter syringe by 8.3% and a kitchen teaspoon by 5.7%.

Women with children were three times more likely to measure the medicine correctly than women without children, results showed. Dosing accuracy was higher in better-educated subjects and those with higher health literacy. Instruction type had no effect. Dosages were most accurate when the 10-milliliter syringe was used. Use of a kitchen teaspoon, which isn't an equivalent measure, could have serious health ramifications related to dosing errors, researchers said. They recommended pharmacies provide standard measuring devices with pediatric medications.

Caveat: Subjects were recruited from a medical clinic and some may have been stressed due to impending appointments, researchers said. The study didn't assess how parents would administer medication over a standard course of treatment involving several days.

Chronic cough: Taking daily iron supplements dramatically improved chronic dry, tickly cough in healthy, nonsmoking women with below-normal iron levels—a condition that affects nearly 20% of child-bearing women—compared with treatments targeting only cough symptoms, according to a small study in the International Journal of Clinical Practice. Cough is more frequent and severe in women than men, and often starts after puberty, researchers said.

Iron deficiency may affect areas of the brain involved in the neurological control of cough, they said.

The study involved 22 women in their late 30s from northern Italy. All had low iron levels and coughs lasting approximately 12.8 months. Their cough severity was rated 3.9 on a scale from 0 (no cough) to 5 (worst cough). Tests showed the subjects had normal lung function and none had asthma. Histamine challenge tests, which measure airway response to allergens, found all 22 had easily irritated, or hyper-responsive, airways.

The study involved two 60-day treatments separated by a month of no treatment. In one, subjects received 10 milligrams of antihistamine once a day and 20 milligrams of proton-pump inhibitor twice a day.

In the other, they received two 330-milligram iron sulphate tablets daily.

Iron supplementation significantly improved cough and histamine hyper-responsiveness compared with antihistamine and proton-pump inhibitor treatment, results showed. Iron levels returned to normal in all but two patients, who were found to have a genetic blood disorder, researchers said.

Caveat: More than 1,000 men were screened for the study but none had chronic cough and low iron, researchers said. The study lacked a control group because administering iron to patients with no iron deficiency would be unethical, they said.

Helpful bacteria: A common bacterium linked to the appearance of peptic ulcers and other stomach disorders may have beneficial properties that help to prevent complications from acid-reflux disease, says a report in Digestive Diseases and Sciences. Helicobacter pylori are found in about half the world's population, often with no discernible symptoms. Higher rates of H. pylori and lower rates of gastroesophageal reflux disease (GERD) are reported in African Americans, compared with white populations, but the association between H. pylori and GERD isn't clear, researchers said.

The study involved 2,020 African Americans, 1,219 women and 801 men, who underwent upper endoscopy, a diagnostic procedure, at a Washington, D.C., hospital from 2004 and 2007. Results showed that 77.1% had gastritis, an inflamed stomach lining, and 2.9% had esophagitis, inflammation caused by stomach acid leaking into the esophagus. Both conditions were found in 18% of subjects, while 2% had normal results and served as controls. Stomach biopsies showed 38% of subjects had H. pylori.

H. pylori were present in 3.8% of patients with esophagitis and 34.4% of controls, but the bacterium didn't result in significant differences between controls and subjects with gastritis or gastritis and esophagitis, the study found. H. pylori may reduce stomach-acid secretions by suppressing ghrelin, a hormone linked to obesity, which is a risk factor for GERD, researchers said. Aggressive efforts to eradicate H. pylori in the general population may explain why African Americans are experiencing a dramatic increase in esophageal cancers, they said.

Caveat: The prevalence of H. pylori infection was found in African American patients treated in a hospital and may not be the same in the general population, researchers said. The control group was small.

Denial and delay: Up to one-third of women diagnosed with inoperable breast cancer initially put off seeing a doctor, often for several months, despite noticeable breast changes, says a report in Acta Oncologica. Public-awareness campaigns stress the importance of mammography screening and early diagnosis to a favorable breast-cancer prognosis. Despite this public focus, cancers are well advanced in many women because of delays contacting the medical system.

To understand those delays, researchers reviewed data from 157 Danish women diagnosed with inoperable or metastatic breast tumors from 2006 to 2011. The data showed 12.1% had waited three to six months after the first symptoms appeared before contacting a doctor, while a wait of six to 12 months was reported by 3.8%. Longer waits of more than one or two years were reported by 18%. A third of subjects had abnormal breast symptoms, including ulcerated tumors and skin changes.

Other health problems, such as depression and anxiety, were reported in 14.6% of subjects and may have overshadowed breast-tumor symptoms, researchers said. About 12% lived in nursing homes and 7.6% had dementia. But 42% of subjects had none of these factors and more than half had neglected obvious symptoms, researchers said. Denial must play a role in their behavior, though improving early detection efforts may not succeed in reaching these women, they said.

Caveat: The study was small and the findings may not apply to women in other countries.

Seeking an Alternative Treatment for Age-Related Eye Conditions

A new compound developed from a fetal-growth protein may provide an alternative to two common treatments for age-related macular degeneration and other eye conditions, and have fewer side effects, researchers said.

Drugs that target angiogenesis, the abnormal growth of blood vessels inside the eye, are the mainstay of therapies for a growing number of eye conditions. The latest issue of Acta Ophthalmologica reports on the study, conducted in China, which involved experiments with a human placenta growth factor molecule called ZY1 that plays a role in gestation. The growth factor is part of a family of such factors that includes vascular endothelial growth factor (VEGF), a protein that stimulates angiogenesis.

Bevacizumab (Avastin) and ranibizumab (Lucentis), the drugs most commonly used to treat angiogenesis, target VEGF, but adverse side effects have been reported with both, researchers said.

This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com.